Amid the pressure, President Ronald J. Daniels said Friday that the university would immediately begin an independent review of how the case was handled, and officials pledged "scrupulous self-examination." Officials also defended their commitment to campus safety.

In the federal complaint, the students allege that failure to disclose the reported rape violates the Clery Act and Title IX, federal laws that dictate how serious crimes like sexual assault should be handled by universities and reported to the public.

The students, who are anonymous in the complaint but represented by the Washington-based advocacy group SurvJustice, urge the federal government to investigate the university's handling of sexual assault in general, arguing that other cases have been bungled.

The incident comes to light in the same week that an Obama administration task force released a report intended to pressure U.S. colleges to do more to combat sexual assault. Also this week, it was revealed that Frostburg State University was under federal investigation for its handling of another alleged rape.

"The university cares about its image of safety, rather than the actual safety of its students," said Mats Dreyer, a Hopkins senior who organized the protest of about 40 students Friday. "A lot of students don't feel safe because they don't feel like they have the information they need to make decisions about their safety."

The students gathered to protest what they say is a culture of silence when it comes to Hopkins holding its own students accountable and taking sexual assault seriously, chanting "Respect over reputation" and "Let us see transparency."

The alleged rape was reported to police in March 2013 in the 3200 block of N. Charles St., at the off-campus, privately owned Pi Kappa Alpha fraternity house named in the federal complaint.

The alleged victim, a Towson University student, went to a hospital for a rape examination and was interviewed by police there, according to a police report. She told officers she had a series of consensual sexual encounters with three men at a fraternity party, at least some of whom were Hopkins students, according to the report. Later, one of the men forced her into non-consensual acts, and two other men joined in, she told police.

"We concluded that there was insufficient evidence to support criminal charges," said Mark Cheshire, a spokesman for the Baltimore state's attorney's office, who declined to provide a more detailed explanation "to respect the privacy of those involved."

Representatives from the Hopkins chapter of Pi Kappa Alpha and its national office did not respond to requests for comment.

Jane Glickman, an Education Department spokeswoman, confirmed that officials had received the Clery Act complaint. The Education Department's Office of Civil Rights has not yet opened a formal investigation into the complaint. Officials don't comment on Title IX complaints.

The Clery Act requires colleges to keep records on and disclose to the public serious crimes that happen on or immediately adjacent to campus property. Title IX, in addition to ensuring gender equity in athletics, also lays out requirements for how universities must handle reports of sexual assault.

The Hopkins complaint filed by SurvJustice contains a lengthy email thread between Hopkins officials. In the emails, the officials debate whether the reported rape allegation by the Towson student at the Pi Kappa Alpha house is subject to the Clery Act's "timely warning" requirement, which obligates universities to warn the community within 90 days about serious or ongoing threats to public safety.

One university official sent an email in June 2013 about growing concerns over the school's obligations under federal law, noting that a group of students were advocating to shut down the fraternity house. The official proposed language to notify the university community of the alleged rape but noted it could draw negative attention to the university, according to a copy of the email in the federal complaint.

DennisO'Shea, Hopkins' spokesman, asked in an email whether the university needed to send the alert before it got an update on the case from prosecutors.

"The situation could either become clear or change radically at that point," he wrote. "I would hate to have waited so long to say something, then say it, and then have the situation evolve quickly, requiring us quickly to say something different."

Hopkins officials declined to answer questions about the case or the complaint but released a statement. O'Shea did not respond to questions about the emails in the complaint.

"The decision not to notify the university community in that case was made after considering relevant facts and legal requirements, and in consultation with the Baltimore police department, which was leading the investigation," university officials said in the statement. "The Johns Hopkins University is deeply committed to the safety and welfare of our community and to ensuring a safe environment for learning and scholarship.

"That commitment includes protecting our students from sexual violence, offering support to victims, dealing firmly and fairly with alleged offenders, and informing students, faculty and staff of serious and ongoing threats to campus safety. For some time, the university has been directly engaged in a comprehensive effort to address students' concerns about campus sexual assault."

Late Friday evening, a Baltimore police spokeswoman issued a statement saying that "the responsibility to disclose and inform the student body and faculty of crimes committed on or around campus rests with that particular school."

Abigail Boyer of the Pennsylvania-based nonprofit Clery Center,which advocates for victims of sexual assault at colleges, said there are several factors universities have to consider when determining whether they need to issue a timely notification under the Clery Act: whether the crime took place on university or university-controlled property, whether issuing the notification would affect a law enforcement investigation, and whether it would result in the victim being identified.

She said timely warning decisions are so case-specific it would be hard to say whether waiting for state's attorney's decisions on prosecution would be a violation of the law.

The Mayor's Sexual Assault Response Team, formed in 2010 in response to concerns about how sex offense investigators were handling cases in Baltimore, did not review the case. Heather Brantner, the coordinator of the team, made up of victims' advocates and law enforcement, focuses on cases that are deemed "unfounded" by investigators, and the case was never marked as such by police.

Laura Dunn, founder of SurvJustice, said the case highlights common trends in how the nation's college campuses handle sexual assault cases.

"We have this idea that rapes are falsely reported, and so we should make sure it really happened and investigate first, but that's not what the law says," Dunn said, referring to the Clery Act.

The alleged Towson University victim is not among the students who filed the complaint; they are concerned Hopkins students, Dunn said. The complaint, submitted in February, also contains a statement from a Hopkins student who believed her alleged rape in 2009 was mishandled by the university.

On Friday, Carrie Andrews, a senior from Philadelphia who also served this year as the president of Hopkins Feminists, recalled last spring when the Hopkins' dean launched a campaign to raise awareness about the importance of seeking and giving consent before sex.

With a protest sign in hand and wearing the T-shirt she received during the awareness campaign, which had the message "Consent is not awkward," Andrews said she couldn't believe the turnaround in events.

"The administration wants to say [they are] being proactive, but they don't really deal with the aftermath," she said. "It was all a PR campaign, to give me this shirt and then not do what they were required to do by law."